The centrifugal compressor used in a compressor part or the like of a turbocharger for an automobile or a ship imparts kinetic energy to a fluid through rotation of an impeller and discharges the fluid outward in the radial direction, thereby achieving a pressure increase by utilizing the centrifugal force.
Such a centrifugal compressor is provided with various features to meet the need to improve the pressure ratio and the efficiency in a broad operational range.
In typical art, for instance, Patent Document 1 discloses a centrifugal compressor provided with a casing having a scroll flow passage formed to have a spiral shape, wherein the height of the scroll flow passage in the axial direction increases gradually from inside toward outside in the radial direction, and reaches its maximum on the radially outer side of the middle point of the flow passage width with respect to the radial direction.